Opportunistic content delivery using delta coding

Abstract

Systems and methods are described for avoiding redundant data transfers using delta coding techniques when reliably and opportunistically communicating data to multiple user systems. According to embodiments, user systems track received block sequences for locally stored content blocks. An intermediate server intercepts content requests between user systems and target hosts, and deterministically chucks and fingerprints content data received in response to those requests. A fingerprint of a received content block is communicated to the requesting user system, and the user system determines based on the fingerprint whether the corresponding content block matches a content block that is already locally stored. If so, the user system returns a set of fingerprints representing a sequence of next content blocks that were previously stored after the matching content block. The intermediate server can then send only those content data blocks that are not already locally stored at the user system according to the returned set of fingerprints.

Description

FIELD[0001]Embodiments relate generally to communications systems, and, more particularly, to opportunistic content delivery using delta coding techniques.BACKGROUND[0002]In many cases, it is desirable to deliver streams or files to the requestor while opportunistically multicasting the same information to others on the network who could potentially be interested in this content at a future point in time. Traditional approaches to prepositioning data streams and files via multicast to remote devices typically involve either: a master copy being maintained on an intermediate server so that when the data is later requested from the remote device, missing data elements or forward error correction codes can later be transmitted to fill in the holes; or remote devices requesting missing data as the multicast is being received.[0003]Additionally, traditional approaches to delta coding and the like rely on keeping track of the information stored on both the client and server sides of a net...

AI Technical Summary

Benefits of technology

The patent describes a system and method for optimizing the delivery of content data from a server to multiple client optimizers over a network. The system includes an object processing subsystem and a communications subsystem. The object processing subsystem chunks the content data into blocks and computes fingerprints of each block. The communications subsystem sends the fingerprints to the client optimizers in advance of the actual content data. The client optimizers compare their locally stored content blocks with the fingerprints and send only the necessary content data to the server. The server optimizer then sends the content data to the client optimizers as a series of chunks, each containing a fingerprint of the previous chunk. The client optimizers use the fingerprints to determine which content blocks are already locally stored and which ones are missing. The system can also include a mechanism for multicasting fingerprints and content data to multiple client optimizers over a network. The technical effects of this system include improved efficiency in delivering content data and reduced network traffic.

Problems solved by technology

Typically, this further involves overhead for keeping the delta coders (e.g., dictionaries and the like) synchronized.

When delta coding is applied to multicast stream distribution, the network overhead for maintaining coder synchronization can be large.

The cost of transmitting delta coder synchronization and forward error correction traffic can impose an especially heavy burden when information is distributed opportunistically if this traffic is sent, whether or not the content is later consumed.

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